.header {
    background-color: #333;
    height: 80px;
}

.nav {
    background-color: blue;
    width: 80%;
    height: 40px;
}

.main {
    background-color: whitesmoke;
    width: 80%;
    height: 1000px;
}

.footer {
    background-color: grey;
    height: 120px;
}


.center {
    margin: 0 auto;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

.white {
    color: white;
}
